Function of a separate NH3-pore in Aquaporin TIP2;2 from wheat

Adam Bertl, Ralf Kaldenhoff

Institute of Botany, Applied Plant Science, Darmstadt University of Technology, Schnittspahnstrasse 10, D-64287 Darmstadt, Germany
FEBS letters Volume 581, Issue 28, 27 November 2007, Pages 5413–5417

Abstract

Functional analysis of heterologously expressed TaTIP2;2 by means of stopped-flow spectrometric studies provide evidence for water and ammonia conductivity. A series of experiments under increasing pH indicate that the gaseous NH(3), rather than the ammonium ion NH(4)(+) was transported. Results from inhibitor studies strongly suggest that NH(3) is not transported in file with water, but through a separate pathway, which could be supplied by the 5th central pore in a tetramer conformation.

Read more